CN106052860B - A kind of optical power monitoring system - Google Patents

Abstract

A kind of optical power monitoring system belongs to optical communication technique and power measurement technical field.It is characterized in that：The shell for carrying inner cavity including one（4）, the Feedback of Power component and optical signal transmission component that be fixed with luminescence component in the lumen, are monitored and generate feedback signal to the power of luminescence component, the light that luminescence component is sent out is irradiated to simultaneously on Feedback of Power component and optical signal transmission component, in shell（4）Upper setting useful signal input pin（9）And signal output pin（1）.In this optical power monitoring system, it is monitored by the luminous power to luminescence component, make in a linear relationship between the luminous power of luminescence component and analog electrical signal to be transmitted, transmitted so as to realize high-precision optical fiber of the analog electrical signal from high-pressure side to low-pressure side using analog form.

Description

An optical power monitoring system

technical field

An optical power monitoring system belongs to the fields of optical communication technology and electric power measurement technology.

Background technique

In the field of power measurement, the measured electrical quantities (such as voltage and current) are usually in a high-voltage environment. For example, the bus current to be measured by a current transformer is usually in a voltage level environment above 10kV, and the surge voltage caused by lightning can reach several hundred above kV. When measuring these quantities, in addition to converting the electrical quantity to be measured to a small signal range that the instrument can accept, it is usually necessary to keep the actual measuring instrument in a low-voltage environment. For true isolation, fiber optics must be used. Therefore, the application of optical devices to the measurement of the power field is a specific application of the field of optical communication in the field of power measurement.

In the existing technology, there are two ways to transmit the information to be measured on the high-voltage side to the low-voltage tester: analog mode and digital mode. One of the application examples of the digital mode is to digitize the bus current value on the high-voltage side, and then pass Optical fibers transmit digital light pulses to electronic current transformers on the low-voltage side. One of the application examples of the analog method is the photoelectric voltage divider measurement system used in the measurement of impulse voltage. The principle is to divide the impulse voltage with a voltage divider to drive the LED to emit light, and then transmit the waveform of the entire impulse voltage with optical fiber. to the low pressure side. Among them, the advantage of the digital method is that it does not have high requirements on the linearity of the light source, so it will not affect its measurement accuracy, but the digital method must be transmitted after sampling the signal to be measured, so it brings power consumption, cost, frequency band, etc. A series of technical problems, so the specific implementation, its implementation is more complicated.

The simulation method is to drive the light source to emit light, and then use the optical fiber to transmit the light emitted by the light source. In the actual implementation, the implementation method is relatively simple and reliable. In the field of optical communication, there are mainly two types of light sources: LED (light-emitting diode) and LD (laser diode). In the prior art, the control of the light-emitting power of this type of light-emitting device is realized by controlling the magnitude of the driving current. . Among them, LD has the advantages of fast response speed, high modulation rate, narrow spectrum, small divergence angle of radiation beam, high output light intensity and high efficiency, but at the same time has poor temperature characteristics, easy damage, and short life. 1. The disadvantage of high price. Compared with LD, LED has the advantages of good temperature stability, low cost and long life.

When using the analog method to transmit the electrical signal to be measured on the high-voltage side to the low-voltage tester, the light-emitting source is generally driven to emit light directly by means of amplitude modulation. There is a high linearity between the signal and the luminous power of the luminous source. However, both LEDs and LDs have their own luminous dead zones, resulting in a non-linear relationship between the luminous power-driving current curve (P-I curve), which directly leads to the failure of the analog method (amplitude modulation method) to achieve high measurement accuracy. The reason is that currently the light-emitting source cannot detect its light-emitting condition when it emits light, and the light-emitting source can only be controlled by a direct method such as a constant current type.

To sum up, when the optical fiber is used to transmit the signal to be tested, if the real-time power of the light source can be detected, and the power of the emitted light reaches a linear relationship with the size of the signal to be tested, then the simulation method can be satisfied. The voltage signal driving the light-emitting source to emit light and the light-emitting power between the light-emitting sources need to have a high linearity requirement, so the measurement accuracy of the optical signal transmission in the analog mode will be greatly improved. In the prior art, when the LD emits light, there are two light output surfaces. In addition to the normal front light output, the back can also receive a certain intensity of light. Using this feature, there are devices on the market that can monitor the power of the LD. LD, because the luminous power of LD is seriously affected by temperature, the main application of this technology design is to realize constant temperature control of LD by monitoring the luminous change of LD, but it is very difficult for this kind of LD to be used for amplitude modulation control, including The reason why LD luminescence is sensitive to temperature will lead to poor accuracy when used. More importantly, when LD is used for modulation, its dynamic range is too small, so at present, LD is more suitable for use in single-mode fiber to achieve large-capacity communication in digital mode. occasions other than AM control applications.

The light-emitting mechanism of LED is different from that of LD. When it emits light, it can only emit light in one direction at a larger radiation angle. Therefore, it is still impossible to monitor the luminous power of LED in the prior art, so no matter whether it is directly controlled or indirectly controlled. The expected linear relationship between the control electrical signal and the luminous power of the LED cannot be achieved.

Contents of the invention

The technical problem to be solved by the present invention is: to overcome the deficiencies of the prior art, to provide an optical device with a power monitoring function capable of monitoring the power of the light-emitting component and an optical power monitoring system, using the optical power monitoring system to monitor The power of the light-emitting component is detected, so that there is a linear relationship between the light-emitting power of the light-emitting component and the analog electrical signal to be transmitted, so that the high-precision optical fiber transmission of the analog electrical signal from the high-voltage side to the low-voltage side is realized by using the analog method.

The technical solution adopted by the present invention to solve the technical problem is: the optical device with power monitoring function, which is characterized in that it includes a shell with an inner cavity, in which a light-emitting component is fixed, and the power of the light-emitting component is monitored. The power feedback component and the optical signal transmission component that monitor and generate the feedback signal, the light emitted by the light-emitting component is irradiated on the power feedback component and the optical signal transmission component at the same time, and the outer shell is provided with a signal input pin for sending a driving signal to the light-emitting component and Signal output pin for outputting the feedback signal generated by the power feedback component.

Preferably, the power feedback component is a photodiode, and the photodiode is fixed on the light-emitting surface of the light-emitting component or on one side of the light-emitting surface of the light-emitting component, and the signal output pin is connected to the terminal of the photodiode.

Preferably, the optical signal transmission component is an optical fiber, the optical fiber is arranged opposite to the light-emitting surface of the light-emitting component, and the optical fiber is introduced into the inner cavity of the housing through an optical fiber interface provided on the housing.

Preferably, the light-emitting component is a light-emitting diode, and the light-emitting diode is fixed on one side of the inner cavity, and the signal input pin is connected to the terminal of the light-emitting diode.

Preferably, a focusing lens for converging the light emitted by the light emitting component is arranged between the light emitting component and the optical signal transmission component.

Preferably, the shell is made of metal or non-metal, and a grounding pin is provided on the surface of the metal shell to realize the grounding of the shell surface.

A kind of optical power monitoring system is characterized in that: comprising:

The current control module, whose input end is connected to the signal to be detected, and whose output end is connected to the signal input pin, is used to generate a variable current signal to drive the light-emitting component to work;

The optical device with power monitoring function, its input end is connected to the current control module, its optical signal output end is connected to the optical signal transmission component, and its electrical signal output end is output through the signal output pin, which is used to realize the optical form transmission of the signal to be detected and output of the feedback signal;

The power detection module, the input end of which is connected to the signal output pin of the optical device with power monitoring function, is used to convert the current signal output by the signal output pin into a voltage signal, and the power detection module is realized by a current-voltage conversion circuit;

The linear relationship determination module, its two signal input terminals are respectively connected to the output terminal of the power monitoring module and the signal to be detected, and its output terminal is connected to the control signal input terminal of the current control module, which is used to judge the output signal of the power monitoring module and the signal to be detected Linear relationship, and output control signal to the current control module.

Preferably, the linear relationship determination module includes a microprocessor and a voltage acquisition circuit connected to the microprocessor, and the voltage acquisition circuit collects the output signal of the power monitoring module and the signal to be detected respectively.

Compared with prior art, the beneficial effect that the present invention has is:

1. In this optical device with power monitoring function, the monitoring of the luminous power of the light-emitting device is realized, and through the optical power monitoring system, the linear relationship between the luminous power of the light-emitting component and the analog electrical signal to be transmitted is achieved, so that The high-precision optical fiber transmission of analog electrical signals from the high-voltage side to the low-voltage side is realized by using the mode method.

2. Through this optical power monitoring system, according to the obtained power information of the light-emitting components, it is judged whether the driving electrical signal of the light-emitting components and the optical power of the light-emitting source have reached a linear relationship, and then the indirect control of the light-emitting components is realized, so there is no need to The light-emitting component is required to work in the linear section, so that the desired linear relationship between the driving electrical signal of the light-emitting component and its luminous power can be achieved.

3. Realize the monitoring of the optical power of the light-emitting diode through the optical device with the power monitoring function.

4. In the optical device with the power monitoring function, only light-emitting diodes, photodiodes and optical fibers for transmitting optical signals are provided, and the structure is simple and the performance is reliable.

5. By setting a focusing lens between the light-emitting diode and the optical fiber, as long as the light irradiated on the focusing lens can be coupled into the optical fiber, it plays a role of focusing and achieves a good coupling effect.

Description of drawings

FIG. 1 is a schematic structural diagram of Embodiment 1 of an optical device with a power monitoring function.

Figure 2 is a schematic block diagram of the optical power monitoring system.

Fig. 3 is a schematic structural diagram of Embodiment 2 of an optical device with a power monitoring function.

Among them: 1. Signal output pin 2. Light emitting diode 3. Photodiode 4. Shell 5. Optical fiber interface 6. Optical fiber 7. Focusing lens 8. Grounding pin 9. Signal input pin.

Detailed ways

Fig. 1～2 is the preferred embodiment of the present invention, below in conjunction with accompanying drawing 1～3 the present invention is described further.

Example 1:

As shown in Figure 1, an optical device with a power monitoring function includes a housing 4, and an inner cavity is arranged in the housing 4. In this optical device with a power monitoring function, the external structure of the housing 4 can be designed as required Any shape (such as a cylinder, a rectangle), the inner cavity is preferably set in the shape of a rectangle. A focusing lens 7 is arranged in the cuboid-shaped inner cavity, and light-emitting diodes 2 and optical fibers 6 are respectively arranged on both sides of the focusing lens 7 . The optical fiber interface 5 can be any current interface type, such as SMA, FC, ST and other interfaces.

The light-emitting diode 2 is preferably packaged in a patch type, the light-emitting diode 2 is fixed on any side wall of the rectangular inner cavity, the optical fiber interface 5 is set on the side wall opposite to the light-emitting diode 2, and the optical fiber 6 is connected with The light-emitting surfaces of the light-emitting diodes 2 are opposite to each other. A group of signal input pins 9 are connected to the cathode and anode of the light emitting diode 2 after being introduced into the inner cavity of the housing 4, and are used to send current signals to the light emitting diode 2 to drive the light emitting diode 2 to emit light.

A photodiode 3 is also fixed in the rectangular inner cavity. A group of signal output pins 1 are introduced into the inner cavity of the housing 4 and connected to the cathode and anode of the photodiode 3. The photodiode 3 generates a current signal after being illuminated by the light-emitting diode 2. The current signal is output from signal output pin 1. In this embodiment, the photodiode 3 is also packaged in a patch type, and the photodiode 3 can be fixed on any side wall of the rectangular cavity except the light-emitting diode 2 and the optical fiber interface 5 . When the shell 4 is made of metal, it is necessary to lead out the grounding pin 8 on the shell 4 to realize the grounding of the shell 4 .

After the light-emitting diode 2 emits light, part of the emitted light enters the optical fiber 6 through the focusing lens 7 , and a part of the light is irradiated onto the photodiode 3 at the same time. After the light emitted by the light-emitting diode 2 irradiates the photodiode 3, the photodiode 3 will send out current signals of different intensities according to the light intensity, and the current signal is output from the signal output pin 1 to realize the monitoring of the luminous power of the light-emitting diode 2. Because the position of the optical fiber 6 introduced through the optical fiber interface 5 is facing the light-emitting surface of the light-emitting diode 2, and a focusing lens 7 that plays a focusing role is arranged between the optical fiber 6 and the light-emitting diode 2, the light emitted by the light-emitting diode 2 is large Part of it enters the optical fiber 6 to realize the transmission of optical signals, and the part of the light emitted by the light emitting diode 2 entering the optical fiber 6 is in multiples of the part irradiated on the photodiode 3 .

Because the light-emitting angle of the light-emitting diode is relatively large, about 120 degrees, by setting the focusing lens 7, as long as the light irradiated on the focusing lens 7 can be coupled into the optical fiber 6, thereby playing a role of focusing. Since the focusing lens 7 plays a role of converging light, the size of the focusing lens 7 is set so that the size of the spot it converges matches the size of the optical fiber 6 to achieve a good coupling effect. In this optical device with power monitoring function, the focusing lens 7 is an unnecessary component. When the light emitted by the light-emitting diode 2 meets the transmission requirements, the focusing lens 7 can be omitted, so that the light emitted by the light-emitting diode 2 can directly irradiate into the optical fiber 6 .

In this optical device with power monitoring function, the light-emitting diode 2 and the photodiode 3 have the following selection criteria when selecting: since the photodiode 3 is used as a monitoring element for the output power of the light-emitting diode 2, the photodiode 3 needs to have a good , that is, if the light power irradiated by light-emitting diode 2 onto photodiode 3 is P _PD , and the photocurrent generated by photodiode 3 is I _PD , then I _PD =c·P _PD (Formula 1), where c is the sensitivity coefficient. In addition to requiring the photodiode 3 to have good linearity, the photodiode 3 also needs to have a temperature coefficient as low as possible.

For the light emitting diode 2 , the frequency band is required to be relatively high, usually dozens of times the highest frequency of the signal to be transmitted. The wavelength of the light-emitting diode 2 is not limited in principle, but in order to reduce the attenuation of the optical signal when it is transmitted in the optical fiber 6, if a plastic optical fiber is used, the wavelength of the light-emitting diode 2 should be selected as 650nm, if a multimode silica fiber is used, then The wavelength of the light-emitting diode 2 should be selected as 820nm. The linearity and temperature coefficient of the light emitting diode 2 are not limited.

As shown in Figure 2, an optical power monitoring system includes a current control module, a signal transmission device, a power detection module and a linear relationship judgment module. The signal S to be transmitted (hereinafter referred to as signal S) is sent to the current control module, the output terminal of the current control module is connected to the input terminal of the signal transmission device, and the signal output by the output terminal of the signal transmission device is sent to the optical fiber 6; the signal transmission device The feedback output terminal of the power detection module is connected to the input terminal of the power detection module, the output terminal of the power monitoring module is connected to the input terminal of the linear relationship judgment module, and the signal S to be transmitted is connected to the other input terminal of the linear relationship judgment module at the same time, and the linear relationship judgment module The control signal output terminal of the current control module is connected with the control signal input terminal of the current control module. The signal transmission device is the above-mentioned optical device with power monitoring function.

As shown in Figure 2, the type of signal S is an AC signal, and the optical power of the optical signal output by the signal transmission device is P _light . The purpose of this optical power monitoring system is to make the output voltage of signal S (denoted as U _signal ) and signal The optical power output by the transmission device is P _light , which satisfies a linear relationship. The relationship between the output voltage U _signal of the signal S and the optical power P _light of the optical signal output by the signal transmission device is:

(1) From the above, it can be seen that the light emitted by the light emitting diode 2 is irradiated into the photodiode 3 and the optical fiber 6, that is, the total power of the light emitting diode 2 is divided into two parts: that is, the light power irradiated on the photodiode 3 is P The power of the optical signal output by _{the PD} and the signal transmission device is P _light , and the optical power is P _PD and the optical power is P _light is a multiple relationship (linear relationship), get: P _light = m · P _PD (Formula 2), where m is a constant, indicating the multiple relationship between the optical power P _PD and the optical power P _light . Meanwhile, according to Formula 1, it can be obtained that: P _light =n·I _PD (Formula 3), where n=m/c .

(2) The current signal output by the photodiode 3 is converted into a voltage signal through the power detection module, so the conversion relationship between the current signal and the voltage signal is a linear relationship, that is, U _monitoring = r·I _PD (Formula 4), r represents The conversion coefficient between voltage and current, such as when the conversion is realized by resistance, r represents the resistance value of the conversion resistance.

(3) Obtained from formula 3 and formula 4: P _light = a · U _monitor (formula 5), where a = m/(c · r) . It can be known from Formula 5 that the optical power P _light entering the optical fiber 6 and the voltage signal Umonitor output by the power _detection module are linearly related.

It can be seen from the above that after the voltage signal U _monitor output by the power detection module and the output voltage U _signal of the signal S are in a linear relationship, the output voltage U _signal of the signal S and the optical power output by the signal transmission device can be equal to P _light . A linear relationship between them is established.

In order to ensure that the linear relationship between the output voltage U _signal of the signal S and the optical power output by the signal transmission device is P _light , the specific implementation method is: the above-mentioned current control module can be controlled by a conventional controllable constant current LED The drive circuit is used to output drive currents of different sizes; the above-mentioned power detection module is implemented by a current-voltage conversion circuit, which is used to convert the current signal generated in the photodiode 3 into a voltage signal (denoted as U _monitoring ), so as to facilitate Monitor. The linear relationship judging module is realized by a microprocessor and a voltage sampling circuit.

Its specific working process and working principle are:

The signal S is connected to the input terminal of the current control module, the current control module starts to work, and outputs a driving current, which is connected to the signal input pin 9 of the above-mentioned optical device with power monitoring function, and drives the light emitting diode 2 to emit light. The part of light-emitting diode 2 entering the optical fiber 6 ( P _light ) is transmitted to the low-voltage side through the optical fiber 6, completing the transmission of the signal S from the high-voltage side to the low-voltage side, and completing the linear relationship of the above formula 2. At the same time, the photodiode 3 outputs a current signal after being illuminated, and the magnitude of the current signal is proportional to the intensity of light, completing the linear relationship of the above formula 3.

The signal output pin 1 is connected to the power monitoring module, and the current signal output by the photodiode 3 is sent into the power monitoring module, and the current signal output by the photodiode 3 is converted into a voltage signal to complete the linear relationship of the above formula 4, and further satisfy Linear relationship of Equation 5. The microprocessor in the linear relationship judgment module performs synchronous sampling on the voltage signal output by the signal S (denoted as U _signal ) and the voltage signal output by the power detection module ( U _monitoring ) through the voltage sampling circuit, and two acquisitions are performed for each monitoring , when the absolute value of the voltage value U _signal /U _monitoring ratio obtained by two samplings is less than a certain threshold, it means that the voltage signal output by the signal S is in a linear relationship with the voltage signal output by the power detection module; if it is in a nonlinear relationship, then The microprocessor controls the current control module to change the magnitude of the driving current to realize the control of the luminous power of the light emitting diode 2, thereby ensuring a linear relationship between the U _signal and the U _monitoring .

Example 2:

The difference between Embodiment 2 and Embodiment 1 is that: as shown in FIG. 3 , in this embodiment, a photodiode 3 with an area smaller than that of the light-emitting diode 2 is used, and the photodiode 3 is not arranged on the side wall of the inner cavity of the housing 4 The photodiode 3 is fixed on the surface of the light-emitting diode 2, so the light-emitting diode 2 will shine on the photodiode 3 after emitting light, and the part of the surface of the light-emitting diode 2 that is not blocked by the photodiode 2 is focused by the focusing lens 7 and enters the optical fiber In 6, the transmission of electrical signals from the high-voltage side to the low-voltage side is realized. Other implementations of Example 2 are the same as Example 1.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention to other forms. Any skilled person who is familiar with this profession may use the technical content disclosed above to change or modify the equivalent of equivalent changes. Example. However, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still belong to the protection scope of the technical solution of the present invention.

Claims (7)

1. An optical power monitoring system, characterized in that: comprising: The current control module, whose input terminal is connected to the signal to be detected, and whose output terminal is connected to the signal input pin (9), is used to generate a variable current signal to drive the light-emitting component to work; The optical device with power monitoring function, its input end is connected to the current control module, its optical signal output end is connected to the optical signal transmission component, and its electrical signal output end is output through the signal output pin (1), which is used to realize the optical signal detection of the signal to be detected. Form transmission and output of feedback signal; It includes a housing (4) with an inner cavity, the inner cavity is rectangular, and a light-emitting component is fixed in the inner cavity, a power feedback component that monitors the power of the light-emitting component and generates a feedback signal, and an optical signal transmission component. The light emitted by the component irradiates the power feedback component and the optical signal transmission component at the same time, and a signal input pin (9) for sending a driving signal to the light-emitting component and a feedback signal generated by the power feedback component are provided on the housing (4) output signal output pin(1); The power detection module, whose input terminal is connected to the signal output pin (1) of the optical device with power monitoring function, is used to convert the current signal output by the signal output pin (1) into a voltage signal. The power detection module adopts current-voltage Conversion circuit realization; The linear relationship determination module, its two signal input terminals are respectively connected to the output terminal of the power monitoring module and the signal to be detected, and its output terminal is connected to the control signal input terminal of the current control module, which is used to judge the output signal of the power monitoring module and the signal to be detected Linear relationship, and output control signal to the current control module. 2. The optical power monitoring system according to claim 1, characterized in that: the power feedback component is a photodiode (3), and the photodiode (3) is fixed on the light-emitting surface of the light-emitting component or fixed on the light-emitting component to emit light On one side of the surface, the signal output pin (1) is connected to the terminal of the photodiode (3). 3. The optical power monitoring system according to claim 1, characterized in that: the optical signal transmission component is an optical fiber (6), the optical fiber (6) is arranged opposite to the light-emitting surface of the light-emitting component, and the optical fiber (6) is set by The fiber optic interface (5) on the housing (4) is introduced into the inner cavity of the housing (4). 4. The optical power monitoring system according to any one of claims 1 to 3, characterized in that: the light-emitting component is a light-emitting diode (2), and the light-emitting diode (2) is fixed on one side of the inner cavity, and the signal input Pin (9) connects to the terminal of LED (2). 5. The optical power monitoring system according to claim 1, characterized in that a focusing lens (7) for converging the light emitted by the light emitting component is arranged between the light emitting component and the optical signal transmission component. 6. The optical power monitoring system according to claim 1 or 3, characterized in that: the housing (4) is made of metal or non-metal, and the surface of the metal housing (4) is provided with a realization housing ( 4) Ground pin (8) for surface ground. 7. The optical power monitoring system according to claim 1, characterized in that: the linear relationship determination module comprises a microprocessor and a voltage acquisition circuit connected with the microprocessor, and the voltage acquisition points are respectively collected from the power monitoring module. output signal and the signal to be detected.